Floating cathode amplifier



Nov. 14, 1933.

T. H. NAKKEN FLOATING CATHODE AMPLIFIER Filed June 12, 1929 2Sheets-Sheet 1 INVENTOR THEUDURUS H. NFMKEN I Y ATTORNEY O 14, 1933- T.H. NAKKEN FLQATING CATHODE AMPLIFIER Filed June 12, 1929 2 Sheets-Sheet2 INVENTOR THEUDURUEI H. NFllKl/(EN Q2 8m w r Wm 3 m Q w@ w N E H N b Iv ATTORNEY sponding power impulses.

Patented Nov. 14, 1933 t 2' 7 1,935,369 V V FLOATING oArno'nn AMPLIFIER.

Thecdorns H.1Nakken, Brooklyn, Y., assignor to Nalrken PatentsCorporation, a

tion of Delaware corpora- Application June 12,1929. Serial No. 370,295 IZ Claims.

This invention relates to amplifiers. The object of the invention is toeifect amplification of feeble electric impulses into substantiallycorre- In carrying out this general object of the invention it isproposed to maintain a substantially fixed plate potential; to

provide means tending to maintain the potential of each grid the same asthat of its corresponding cathode; and to permit cathodes and grids tofluctuate as to their potential in response to the sig nailing impulsesand relatively to the substantially fixed potential of the plates.

In embodying my invention I contemplate the employment of thermionictriode amplifier tubes iments of the invention solely for purposes ofillustration and not limitation. These embodiments are described in thefollowing specification in connection with the accompanying drawingswhich form a part hereof.

In the drawings, Fig. 1 is a diagram illustrating one form of theinvention; and Fig. 2 is a similar diagram illustrating the invention ina modified form.

4 In my amplifier assemblage I employ a plurality oi thermionic triodeamplifiers A, A1, A2 and A2, each comprising a'plate P, a grid G, and acathode C. I preferably employ the type of tube in which the cathode Cis heatableto a state of electron emission by a separate heating elementinsulated from the cathode and with the cathode free from capacitycoupling with its heater. Prei'er ably the tubes A2 and A2 are of thepower type. The secondary 1 of an inputtransformer 2 has W its terminalsconnected respectively to the cath- -odes and the grid of tube A.

In Fig. 1, a conductive lead 3' connects one terminal of secondary 1with cathode C while a condenser 4 serves as a link means to connect theopposite terminal with the grid G.

In Fig. 2, the capacity link and the conductive link are reversed inposition as indicated by the conductive link 3 and the condenser 4.

Between the stage A and A1 is provided an intercg stage transformer 21.Its primary is directly connected with the cathode C from the negativeterminal of a suitable source of direct current plate potential. Itssecondary has its terminals connected respectively by a conductiveconnection 31 .and a condenser link 41 with the cathode and grid of tubeA1. The primary of a third transsignal comiru through the amplifier.

the plate circuit sourcewith the cathode C of tube Aiwhileits secondaryis in the form of two The terminals of each separate coils l2 and 1'2.of these separate coils are connected respectively by means of aconductive link 32 and capacity link 42 with the cathode and grid oftube A2 while the terminals of coil 1'2 are respectively connected byconductive link 32 and capacity link 4'2 with'the cathode and the gridof tube A2. Respective cathodes C of tubes A2 and A2 are connected toopposite terminals of the two-part primary 5 and the center point ofwhich is connected through main 6 with the negative terminal 20. Thesecondary 13 of this transformer supplies power to any desiredtranslating device.

In the amplifier of Fig. 1, each grid is connected by its respectivehigh resistance or leak resistance R, R1, R2 and R2 with the negativeterminal 20. v

The plates of tubes A and A1 are both connected to the plus to terminalof the plate current source while the plates P of tubes A2 and A2 areconnected to the plus 450 terminal of the plate current source.

Referring now more particularly to Fig. 2, the same connections exceptthat the conductive and capacity link means between each transformersecondary and the associated cathode and grid of the tubes which theycontrol are reversed from the connections shown in Fig. 1. In addition,the leak resistances R, R1, R2 and R'2 are connected between thenegativeterminal 20 and the terminal of the transformer secondary farthest fromthe grid G at a point preferably adjacent to the condenser operationwith no excitation of the cathodes to effect electron emission and withno All cathodes and grids are at the same potential, preferably the fullnegative of the system as indicated by the connections described. Theplates are all conductively directly connected to their proper valuepositive voltage terminal. Upon excitation of the cathodes into a statecapable of emitting electrons, these cathodes as well as the controllinggrids G float as to their potential in response to signalvariationswhile the transformer secondaries fulcrum on the potential ofthe cathode to which they are connected and apply to the associated grida potential relativelyto the cathode which fluctuates in accordance withthe terminal fluctuation of the said transformer secondaries.

What I claim and desire to secure by United States Letters Patent is:

1. In combination in an amplifier assemblage, a triode thermionicamplifier comprising a cathode having a separate heater, a plate and agrid; an input transformer having a secondary coil Well insulated fromits core and primary winding; a source of direct current plate circuitpotential having a negative terminal and a'positive terminal; an outputtransformer having'a primary coil; electric connections connecting theplate of said triode amplifier to the positive terminal of said sourceof direct current potential and said primary coil between the cathode ofsaid triode amplifier and said negative terminal of said source ofdirect current potential; said secondary coil having terminalconnections to the cathode and to the grid of said triode amplifierincluding a condenser; and a leak resistance conductively connecting thegrid of said triode amplifier with said negative terminal and leavingsaid cathode free from conductive connection with said negative terminalby the interpositioning of said condenser, except that said cathode isconnected to the free high potential end of the 7 primary coil of saidoutput transformer and is free to partake of the instantaneouspotentials thereof. 7

2. In a thermionic triode amplifier assemblage, a plurality of triodeamplifiers each comprising a plate, a grid and a cathode having anelectrically separate heating element; a source of direct current platecircuit potential having a negative terminal and a positive terminal; adirect conductive connection between said positive terminal and theplates of said triode amplifier; a transformer coil connected betweeneach said cathode and said negative terminal, each said cathode beingmaintained free from any direct connection withground and with saidsource of direct current plate circuit potential; a leak resistanceconnecting each saidgrid with said negative terminal; and an input coil;link means connecting the ends of said coil respectively to the grid andthe cathode of each said triode amplifier including a condenser betweensaid cathode and one end of said coil, whereby in response to signalsthe cathode and grid potentials fluctuate relatively to each other.

' TH. H. NAKKEN.

